This invention relates to an aerodynamic device that controls the underbody air flow of vehicles.
As a car, truck or other vehicle travels along the road, it disturbs the air through which it passes. This air disturbance has important consequences for environment, reduction of energy consumption, safety, and road handling performance of the vehicle.
As to the environment, and energy consumption, overcoming the wind resistance and turbulence generated by the passage of the vehicle expends energy. That energy is supplied by the fuel of the vehicle. The greater the wind resistance and turbulence, the greater the expenditure of fuel and the lower the fuel economy. The increased fuel usage impacts the environment directly through increased emissions, and indirectly through increased demands for the production of fuel.
As to safety, the turbulence produced by vehicles, particularly large trucks, imposes sideways forces directly on passing vehicles, reducing their stability. The turbulence also results in decreased visibility during wet road conditions. Most drivers are familiar with the great amount of side spray produced by large trucks in rainy or snowy conditions, which can obscure visibility behind and to the sides of the truck.
The effects of aerodynamics on road handling performance of the vehicle are relatively minor for conventional vehicles, but it is quite noticeable for race cars. Race cars travel sufficiently fast that the aerodynamic lift generated by the passage through the air may reduce road contact load, leading to reduced control of the vehicle in corners.
The effects of aerodynamics, safety, and road handling performance have been recognized and addressed in the past. Vehicles are made with an aerodynamic upper body configuration to reduce wind resistance, consistent with other requirements of the vehicle. For example, in recent years overcab air deflectors on trucks used to pull trailers have become popular to reduce wind resistance. Rear spoilers are used to alter the aerodynamics of race cars and some production cars. Mud flaps and side guards are used to reduce side spray, although drivers will recognize that such devices are, at best, of limited value. Side spray remains a substantial highway safety problem. Some race cars use underbody air dams to alter the aerodynamic loadings, although the principles have not been successfully applied to highway vehicles.
Although these and other techniques have been used to alter the aerodynamics of highway vehicles, they have had only limited success. There remains a need for an approach for improving fuel mileage and reducing side spray safety problems. The present invention fulfills this need, and further provides related advantages.